Power supply management controller integrated circuit, power management circuit for electrically powered systems, and method of managing power to such systems

ABSTRACT

The present invention provides a power supply management controller integrated circuit for managing power supply to one or more system units of a system, said integrated circuit comprising power supply means for powering said system units, a power supply control unit for controlling said powering of said system units, a wake-up timer unit, and means for acknowledging an active or passive state of said system, wherein said power supply control unit is arranged for cooperating with said means for acknowledging said state of said system for enabling said power supply control unit to cease powering of said system units for de-activation of said system during said passive state of said system, and for enabling said power supply control unit to maintain powering of said system units during an active state of said system, and wherein said power supply control unit is ranged for cooperating with said wake-up timer unit for periodically powering said system units during said passive state of said system for enabling activation of said system.

FIELD OF THE INVENTION

The present invention is directed to a power supply managementcontroller integrated circuit for managing power supply to one or moresystem units of a system, a power management circuit for electricallypowered systems using such an integrated circuit, and to a method ofmanaging power supply to such a system.

BACKGROUND OF THE INVENTION

With the continuing shrink of silicon device sizes, the processing speedof digital signal processors and micro controllers keeps on growing.However the current consumption is rising too. In many electronicsystems high processing speed is only needed during short periods ofoperation. The rest of the time such systems are in a sleep mode orstandby mode at a very low activity level. However the systems cannot befully shut off as they must be able to resume full operation in a veryshort period of time. In particular as a result of high leakage currentstypical for silicon devices there is still significant supply currentbeing drawn by the systems in sleep mode or standby mode. It will beappreciated that this is not desired from the point of view of energyconservation. Moreover, due to this inefficient use of available energy,many of these type of applications must be powered by mains voltage or aby a durable, large capacity power source that enables operation over asufficiently long period of time. Battery operation is often notpossible, or results in the application being large and bulky, and astherefore difficult to handle or install.

SUMMARY OF THE INVENTION

The present invention is directed to resolving the above mentionedproblem, and providing a power management controller which is small,fast, reliable and accurate.

To this end, the present invention provides a power supply managementcontroller integrated circuit for managing power supply to one or moresystem units of a system, said integrated circuit comprising powersupply means for powering said system units, a power supply control unitfor controlling said powering of said system units, a wake-up timerunit, and means for acknowledging an active or passive state of saidsystem, wherein said power supply control unit is arranged forcooperating with said means for acknowledging said state of said systemfor enabling said power supply control unit to cease powering of saidsystem units for de-activation of said system during said passive stateof said system, and for enabling said power supply control unit tomaintain powering of said system units during an active state of saidsystem, and wherein said power supply control unit is arranged forcooperating with said wake-up timer unit for periodically powering saidsystem units during said passive state of said system for enablingactivation of said system.

The integrated circuit of the present invention enables complete shutdown of the one or more system units in the system, or the completesystem as a whole (dependent on the application).

The integrated circuit takes over all critical system functions when thesystem is in the de-activated state, and is able to wake-up the fullsystem in a fast and time accurate way. This allows the use of fastsignal processors in battery operated equipment or in equipment operatedfrom an unreliable energy source.

In particular, since the integrated circuit of the present inventionperiodically powers the system units during the de-activated state ofthe system, power supply management controller integrated circuit of thepresent invention makes it possible for the system to wake-up as soon asactivation of the system is required for processing data or otherfunctions.

The means for acknowledging an active or passive state of the system maybe integrated in the power supply control unit of the integratedcircuit. In particular, the power supply control unit may be able todetect the active or passive state of the system based on voltagedifference, amount of current being drawn, or the temperature of thesystem units being monitored. Moreover, the means for acknowledging anactive or passive state of said system may be connected to a sensorsignal input for receiving sensor signals from a sensor unit. Such asensor unit may for example be at least one element of a groupcomprising an internal sensor unit of said integrated circuit, amicro-electro-mechanical systems (MEMS) based sensor such as a pressuresensor implemented on said integrated circuit, an external sensor unit,a voltage level sensor, a current sensor or a temperature sensor. Itshould be appreciated, however, that other types of sensor units may beused as well, e.g. dependent on the application.

The terms ‘active’, ‘passive’, ‘de-activated’ and ‘activated’ are to beinterpreted as follows. The active or passive state of the system refersto the presence or absence of a requirement for the system to performits functions, i.e. data processing, interaction between system units orperforming specific tasks of the system. A passive state thus refers toa state wherein the system is activated, but without performing anyrequired activity (e.g. a wait-state or idle state). De-activation oractivation refers to the power supply management controller integratedcircuit switching off power to the system units under control, andtaking over the system critical functions (e.g. providing a clocksignal). In this respect, activation and wake-up both refer to thesystem being powered on by the integrated circuit of the invention,after a period of de-activation. De-activation turns the system to ade-activated or standby mode by cutting off power to the system unitsunder control, and taking over critical system functions by theintegrated circuit.

According to another embodiment of the invention, said integratedcircuit further comprises a clock unit for providing a clock signal forsaid wake-up timer unit. A clock unit enables accurate operation of thewake-up timer, and makes the integrated circuit self-supporting in thatit does not have to rely on an external clock circuit. Moreover, theaccurate clock unit of this embodiment provides a clock signal that canbe used by external units, such as system units that rely on an accurateclock signal even during a de-activated state of the system.

The clock unit may be operatively connected to an oscillator unit. Suchan oscillator unit may comprise any of a group comprising a crystaloscillator or a controlled oscillator. In case a controlled oscillatoris present in the clock unit, this oscillator comprises tuning meansarranged for periodically tuning said controlled oscillator according toa duty cycle, and wherein said tuning means are arranged for adaptingsaid duty cycle dependent on a tuning signal which is indicative of anenvironmental parameter. Accurate tuning of the oscillator may beachieved by means of a suitable combination of a phase locked loop, adelay locked loop, and/or a frequency locked loop in a manner known tothe skilled person.

A special feature of this embodiment is that tuning is performedperiodically according to a variable duty cycle. The tuning cycle ismade dependent on parameters that may influence the oscillationfrequency. Such parameters include, amongst others, the temperature ofthe oscillator or the rate of change of this temperature. The presentembodiment is designed to perform tuning more intensively (by amendingthe duty cycle within which tuning is performed) or less intensivelydependent on the need for tuning.

As mentioned, the clock unit may comprise a crystal oscillator. Inparticular, this may be a low power high frequency oscillator with thefollowing characteristics: very low current consumption, fast start-uptime, programmable power modes. The high frequency oscillator mayprovide a clean reference clock to system units, such as radio devicesand/or high speed data converters in a system.

The start-up time of a crystal oscillator is generally interpreted asthe duration of time required for the oscillator circuit to generate astable and desired oscillation signal from the time of power-on. In apreferred embodiment, the fast start-up time and programmable powermodes are based on precision control of the amplitude of oscillation. Inthis embodiment, a low-power mode of the crystal oscillator is achievedby reducing the oscillation amplitude to a low level, while inhigh-power mode the amplitude is increased for providing a strong clockreference signal. Transition from the low-power mode to the high-powermode can be performed relatively fast. This principle is used forproviding the short start-up time and fast start-up. In this embodiment,start-up is thus performed by switching the oscillator from a low-powerto a high-power mode, instead of switching the oscillator from no powerto power-on. Moreover, since the low-power and high-power levels areprogrammable (the amplitude is programmable), the start-up time can beinfluenced by selecting/optimizing suitable power levels.

According to another embodiment of the invention, integrated circuit maycomprise a transducer interface for enabling said integrated circuit tobe operatively connected to an (external) transducer. This enablesconnection of transducers to monitor specific system parameters whichcannot be monitored with the on-chip provided transducers (e.g. gas orpressure). Such parameters may be indicative for a need to ‘wake-up’ thesystem from a de-activated state as facilitated by the power supplymanagement controller integrated circuit of the present invention. Inrelation to this, it is noted that apart from periodic powering of theone or more system units during said de-activated state of said systemfor enabling activation of said system, the power supply control unitmay be arranged to wake-up the system on detection of a voltage level ortemperature within the system which exceeds or drops below a certainpreprogrammed threshold. In that case, in order to control such aparameter, the system may require to take action immediately (e.g. byregulating a voltage, switching on a ventilation unit or other coolingmeans, or the like).

According to another embodiment, said integrated circuit comprises acommunication interface for reading or writing data to said integratedcircuit. The integrated circuit may be arranged for programming ofoperation parameters of said circuit, using the communication interface.The communication interface may comprise a serial or parallel digitalinput or output, for writing or reading said data. Communication may ofcourse also take place in a different suitable way.

The term power supply means, as used herein, should be interpreted toinclude a power supply input, such as an input voltage connector, whichenables the integrated circuit to be connected to an external powersource, such as a battery, mains voltage adapter or transformer unit, analternative suitable AC or DC power source, or an energy harvestingdevice (i.e. for deriving energy from external sources, such as solarpower, thermal energy, wind energy, salinity gradients, and kineticenergy). Integrated circuit according to any of the previous claims,wherein said power supply means comprise an input voltage connector forreceiving power from an external power source.

According to a second aspect of the invention, there is provided a powersupply management circuit comprising an integrated circuit as describedabove.

According to a third aspect of the invention, there is provided a methodof managing power supply to one or more system units of a system,wherein said system units are powered by power supply means, and whereinsaid powering of said units is controlled by a power supply controlunit, said method comprising a step of: acknowledging an active orpassive state of said system; said power supply control unit managingsaid supply by ceasing powering of said system units for de-activationof said system during said passive state of said system, and maintainingpowering of said system units during an active state of said system, andsaid power supply control unit periodically powering said system unitsduring said passive state of said system for enabling activation of saidsystem.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be further elucidated through description ofan embodiment thereof, with reference to the enclosed drawing, wherein:

FIG. 1 is a schematic layout of an integrated circuit according to anembodiment of the present invention.

DETAILED DESCRIPTION OF THE DRAWING

The invention is directed to a largely analog integrated device (alsoreferred to as power supply management controller integrated circuit)that enables complete shut down of other devices in a system (e.g.devices characterized by high leakage current). The integrated circuittakes over all critical system functions in standby or de-activated modeand is able to wake-up the full system in a fast and time accurate way.This will allow the use of fast signal processors in battery operatedequipment or in equipment operated from an unreliable energy source.

The key function of the Integrated circuit is to be the system referencefor supply (voltage) and time (clock signals) as well as being a monitorof the system's operating conditions. The integrated circuit has ultralow current consumption and therefore never has to be switched off inpractice. The integrated circuit has one or more of the functions listedbelow. How the functions interact is shown in the block diagram.

FIG. 1 illustrates the layout of an integrated circuit 9 in accordancewith an embodiment of the present invention. In FIG. 1, the integratedcircuit 9 comprises a power supply voltage regulator or power supplycontrol unit 1, a real time clock 2, a high frequency oscillator 3, acontrolled oscillator 4, programmable timers 5 (in this embodimentintegrated with real time clock 2), temperature and/or voltage monitors6 (in this embodiment integrated with the power supply control unit 1),a transducer interface 7, and serial digital interface 8.

Power supply control unit 1, comprising one or more voltage regulators,creates the supply voltage for other system parts. This supply voltageis provided through outputs VD1 and VD2 of the integrated circuit, beingconnected to output terminals 14 and 15 in FIG. 1. The regulators in thecontrol unit 1 can be shut-off and their output can be disabled to fullyshut down connected system parts. A power-on reset circuit is part ofthe power management system and produces a logic signal (pok) when thesupply voltage has reached a predefined and stable level. Although anysuitable power source may be applied, in the present embodiment, theintegrated circuit 9 receives its power via supply voltage inputs 16 and17, through input 18 (VDD) of the integrated circuit 9.

The real time clock 2 can either be based on a crystal oscillator 3 or aControlled Oscillator (CO) 4, or both. High frequency oscillator 3comprises a crystal based oscillator with the following specialcharacteristics: very low current consumption, fast start-up,programmable power modes. The high frequency oscillator provides a cleanreference clock to, for example radio devices (not shown) and/or highspeed data converters (not shown) in the system. This (reference) clocksignal is provided to the system units via outputs 10 and 11 (CLOCK out)of the integrated circuit.

The fast start-up time and programmable power modes are based onprecision control of the amplitude of oscillation. A low-power mode ofthe crystal oscillator is achieved by reducing the oscillation amplitudeto a low level, while in high-power mode the amplitude is increased forproviding a strong clock reference signal. Transition from the low-powermode to the high-power mode can be performed relatively fast. Thisprinciple is used for providing the short start-up time and faststart-up. In this embodiment, start-up is thus performed by switchingthe oscillator 3 from a low-power to a high-power mode.

Controlled oscillator 4 is a low frequency oscillator which isperiodically tuned by a low power but high frequency crystal oscillator3. Under duty cycle control. The tuning is performed using a combinationof a Phase Locked Loop (PLL), a Frequency Locked Loop (FLL) and a DelayLocked Loop (DLL). The tuning is performed according to a duty cycle.The controlled oscillator uses adaptive duty cycle control for thetiming of the tuning of the oscillator. The duty cycle depends on therate of change of environmental factors, such as temperature.

Programmable timers 5 are used to wake-up system parts at apre-programmed time. The timers are controlled based on the clock signalprovided by the clock unit 2. A wake-up timer unit causes providing atrigger signal to the power supply control unit at the end of acount-down cycle for temporarily powering the system units, such as toenable the system to be activated if required. If the system is requiredto activate from a de-activated state, this may either be detectedwithin the power supply control unit 1, or alternatively the system mayprovide an indication signal to the integrated circuit.

One of the timers 5 is a watchdog counter which resets the system if ithas detected that the system has unintentionally entered a locked-upmode. The watchdog counter is a digitally implemented pulse counterwhich is preset and counts down to zero. When the zero count is reacheda logic signal is generated which can be used to reset or restart (partof) the system. The counter is periodically preset by the system toprevent that the zero count will be reached during normal operation. Ifzero count is reached then this means that normal system operation isnot possible anymore (e.g. due to a software bug or other systemfailure) an a reset is necessary.

The temperature and voltage monitors 6 are monitor circuits that createtrigger signals (e.g. wake up signals) to other parts of the system incase certain pre-programmed thresholds have been exceeded.

The transducer interface 7 allows the connection of transducers to theintegrated circuit for monitoring specific system parameters whichcannot be monitored with the on-chip provided transducers (e.g. gas orpressure).

Serial digital interface enables communication with the integratedciruit during normal system operation. It can be used to write settingsto or read parameters form the device. It can also be used to provideprogramming data to the integrated circuit for programming itsoperational parameters.

1. Power supply management controller integrated circuit for managingpower supply to one or more system units of a system, said integratedcircuit comprising power supply means for powering said system units, apower supply control unit for controlling said powering of said systemunits, a wake-up timer unit, and means for acknowledging an active orpassive state of said system, wherein said power supply control unit isarranged for cooperating with said means for acknowledging said state ofsaid system for enabling said power supply control unit to ceasepowering of said system units for de-activation of said system duringsaid passive state of said system, and for enabling said power supplycontrol unit to maintain powering of said system units during an activestate of said system, and wherein said power supply control unit isarranged for cooperating with said wake-up timer unit for periodicallypowering said system units during said passive state of said system forenabling activation of said system.
 2. Integrated circuit according toclaim 1, wherein said means for acknowledging said state of said systemare comprised by or integrated within said power supply control unit. 3.Integrated circuit according to claim 2, wherein for acknowledging saidstate of said system, said power supply control unit is arranged fordetecting current or current variations of a supply current provided tosaid system units.
 4. Integrated circuit according to claim 1, whereinsaid means for acknowledging an active or passive state of said systemare connected to an sensor signal input for receiving sensor signalsfrom a sensor unit.
 5. Integrated circuit according to claim 4, whereinsaid sensor unit comprises at least one element of a group comprising aninternal sensor unit of said integrated circuit, amicro-electro-mechanical systems (MEMS) based sensor such as a pressuresensor implemented on said integrated circuit, an external sensor unit,a voltage level sensor, a current sensor or a temperature sensor. 6.Integrated circuit according to claim 1, further comprising a clock unitfor providing a clock signal for said wake-up timer unit.
 7. Integratedcircuit according to claim 6, wherein said clock unit is operativelyconnected to an oscillator unit, said oscillator unit being at least oneof a group comprising a crystal oscillator or a controlled oscillator.8. Integrated circuit according to claim 7, wherein said oscillator unitis a controlled oscillator, and wherein said oscillator comprises tuningmeans arranged for periodically tuning said controlled oscillatoraccording to a duty cycle, and wherein said tuning means are arrangedfor adapting said duty cycle dependent on a tuning signal which isindicative of an environmental parameter.
 9. Integrated circuitaccording to claim 8, said tuning means further comprising means forproviding said tuning signal being indicative for at least one of agroup comprising temperature, rate of change of temperature. 10.Integrated circuit according to claim 1, further comprising a transducerinterface for enabling said integrated circuit to be operativelyconnected to a transducer.
 11. Integrated circuit according to claim 1,further comprising a communication interface for reading or writing datato said integrated circuit.
 12. Integrated circuit according to claim11, said integrated circuit being arranged for programming of operationparameters of said circuit.
 13. Integrated circuit according to claim 1,wherein said power supply means comprise an input voltage connector forreceiving power from an external power source.
 14. Power managementcircuit for an electrically powered system, said power managementcircuit comprising a power supply management controller integratedcircuit according to claim
 1. 15. Method of managing power supply to oneor more system units of a system, wherein said system units are poweredby power supply means, and wherein said powering of said units iscontrolled by a power supply control unit, said method comprising a stepof: acknowledging an active or passive state of said system; said powersupply control unit managing said supply by ceasing powering of saidsystem units for de-activation of said system during said passive stateof said system, and maintaining powering of said system units during anactive state of said system, and said power supply control unitperiodically powering said system units during said passive state ofsaid system for enabling activation of said system.